The present invention relates generally to the testing of an internal combustion vehicle and more particularly to an improved method for determining the gasoline mileage or fuel economy of such a vehicle.
Presently, fuel economy measurements are performed on a dynamometer. A test apparatus is coupled to the fuel and/or exhaust system of the vehicle under investigation by transducers, and the vehicle is then operated under predetermined conditions, i.e., the vehicle is "driven" through a prescribed test cycle.
In terms of time and cost, the existing test cycle procedures are totally inappropriate for use in vehicle repair and service situations. For example, the test cycle of the EPA fuel economy procedure is far too extensive and complicated to be performed efficiently at the service and repair level. In other words, the length of test cycle and the equipment necessary to control the vehicles during the test (such that repeatable figures are obtained) simply cannot be justified at this level.
Further, the existing procedures fail to realistically forecast "on the road" mileage. Although the fuel economy numbers are reliable for purposes of comparison, the actual road mileage for a given vehicle is often substantially less than the predicted fuel economy.
The availability of realistic and readily ascertainable fuel economy figures is, however, particularly significant in the effort to reduce fuel consumption, and the lack of a simple and quick procedure for generating reliable figures has a serious adverse effect. First, it is difficult to advocate fuel-conscious driving techniques when the underlying support, i.e., the fuel economy figures, is erroneous and therefore unbelievable. Second, vehicle maintenance and repair are often proposed on the basis of improved fuel economy. Again, without reliable figures, the inducement to maintain and/or repair is substantially lessened.